Device for determining thermal-oxidative stability of oils

Abstract

FIELD: lubricants.SUBSTANCE: invention relates to laboratory equipment for assessing the performance properties of oils. The invention concerns a device for determining the thermal-oxidative stability of oils, comprising a heating element, on the upper surface of which a metal disk for mounting samples is located, connected in series with a linear autotransformer and with a thermostat, a thermocouple, a radiator, an inductor as a power source and a fan with a power supply unit connected to a switch, through which the entire device is connected to a power supply from a 220 V household network, wherein a solid-state relay mounted on the radiator is used as the autotransformer, the thermostat is a control unit, through which the inductor is connected in series to the switch, and the heating element is a metal disk, in the upper surface of which a radial recess is made for placing a measuring thermocouple connected to the control unit.EFFECT: increasing the safety of determining the thermal-oxidative stability of oils with high accuracy of heating temperature control.1 cl, 1 dwg, 1 ex

Description

[0001] The invention relates to laboratory equipment for assessing the performance properties of oils, in particular for determining thermal-oxidative stability (TOS) in research physicochemical laboratories or laboratories of storage warehouses and enterprises producing oils.

[0002] The TOC of oils characterizes their ability to resist chemical degradation and oxidation under the influence of high temperatures and atmospheric oxygen. It determines the oil's resistance to the formation of varnish deposits, sludge, and increased viscosity. Therefore, developing a device for accurately and safely determining the TOC of oils is a pressing issue.

[0003] TOC testing involves heating an oil sample for a specified time under specific conditions and recording changes in its operating parameters and physicochemical properties. Various devices are currently used for such tests. In some, oxidation occurs with a forced supply of air or oxygen, while in others, gas exchange above the sample occurs through natural convection, but with a catalytic effect of the container material on the heated sample.

[0004] A device for determining the TOC of oils is known (GOST 981-75), consisting of a trap, a precision measurement vacuum gauge (VTI), a rheometer or rotameter and an oil bath.

[0005] The disadvantage of this installation is the low safety of its operation. due to the need to supply oxygen to the heated sample, which is explosive.

[0006] A device for determining TOC and corrosion activity (GOST 20944-75) is known, consisting of a reactor, thermostat, gas bubbler, eight-ball condenser, rheometer, low-pressure reducer, and drying system. The device operates by oxidizing liquids in contact with metals and air when heated to 200°C or with industrial nitrogen when heated to 300°C. 0 With the use of the device.

[0007] A device for determining the thermal-oxidative stability of bulk oil (GOST 23797-79) is known. It consists of a thermostat, an aluminum beaker, a reactor, an air supply tube, metal plates, a condensate receiver, a condenser, a rheometer, columns with cotton wool, ascarite, silica gel indicator, fine-pored and coarse-pored silica gel, calcium chloride, a thermocouple, and a thermometer. The device operates by continuously bubbling air through a specified volume of oil in the presence of catalysts at a given temperature. The thermal-oxidative stability is then assessed based on the amount of sediment formed, insoluble in isooctane, by changes in viscosity, acid number, and the presence of deposits in the reaction vessel, as well as the corrosivity of the oil based on changes in the mass of the catalyst plates.

[0008] The disadvantage of these devices is low safety due to the forced supply of air, oxygen or the catalytic effect of the container material on the heated sample, which is explosive.

[0009] A device for assessing the performance properties of lubricating oils is known (STO Gazprom 2-2.4-134-2007), which we took as a prototype. Oil oxidation is carried out on the Papok-R device under the influence of atmospheric oxygen at a heating disk temperature of (180±3)°C and the catalytic action of the steel from which the cups are made, for 3 and 6 hours. The Papok-R device consists of a control unit, a "Network" toggle switch, a process unit, a grid, a disk, a door, a temperature sensor, a recess for the temperature sensor, an opening for the temperature sensor, an opening for a standard thermometer, a recess for a standard thermometer, a display, buttons and a control knob, an input for the temperature sensor, an input for the power cord, a holder for fusible links, a "ground" terminal, and an RS-232 connector.

[0010] The disadvantages of the prototype are: low safety due to the lack of a design feature to automatically de-energize the device in the event of a short circuit or hot oil spill on the surface; the use of a relay thermostat and a linear autotransformer increases the risk of sparking during device operation; the use of a resistance heating element (ohmic heating element) increases the risk of ignition of the vapors of the tested oil, since there is an element with a temperature above the flash point of flammable liquids (FL); low accuracy of disk heating temperature control due to the fact that the thermocouple is installed on the surface of the metal disk at the edge and perpendicular to it, and the relay-type thermostat does not provide smooth adjustment of the test temperature.

[0011] The technical problem solved by the proposed invention is the creation of a safe device for determining the thermal-oxidative stability of oils with high-precision control of the heating temperature.

[0012] The technical result of using the proposed invention consists in increasing the safety of determining the thermal-oxidative stability of oils with high accuracy of heating temperature control.

[0013] The technical result is achieved in that a device for determining the thermal-oxidative stability of oils contains a heating element, on the upper surface of which a metal disk for mounting samples is located, connected in series with a linear autotransformer and with a thermostat, a thermocouple, a radiator, an inductor as a power source and a fan with a power supply unit connected to a switch, through which the entire device is connected to power from a 220 V household network, wherein a solid-state relay mounted on the radiator is used as an autotransformer, the thermostat is a control unit, through which the inductor is connected in series to the switch, and the heating element is a metal disk, in the upper surface of which a radial recess is made for placing a measuring thermocouple connected to the control unit.

[0014] The essence of the invention is explained by the following examples and Fig. 1.

[0015] The device for determining the thermal-oxidative stability of oils consists of any inductor (1) with an output power of at least 1.5 kW, electrically connected to the power supply from a 220 V household network in series through a solid-state relay (2) installed on the radiator (3), a control unit (4) and a switch (5). Any control unit with feedback with the unit's power inputs, control voltage output and signal input from a measuring thermocouple, for example, REX C-100, can be used as the control unit (4). Any solid-state relay of the inductor supply voltage, for example, SSR-50 DA, can be used as the relay (2). Any radiator, for example, an aluminum plate-type radiator, can be used as the radiator (3).

[0016] A metal disk (6) is installed on the upper surface of the inductor (1), which is an active heating element. The disk (6) is for placing steel cups with samples of the tested oil with a diameter of 100-120 mm and a thickness of 10 to 15 mm. The disk (6) can be made of any ferromagnetic metal, for example, steel grade 09G2S. On the upper surface of the disk (6), in the direction from the edge to the center, there is a radial recess with a diameter 0.1 mm larger than the diameter of the thermocouple (7), in which a measuring thermocouple (7) is placed, electrically connected to the control unit (4). A measuring thermocouple of type K (Chromel-Alumel) can be used as a thermocouple (7).

[0017] A fan (8) is installed at a distance of 2±0.5 cm from the radiator (3), connected to a 220V household power supply in series via the power supply (9) and switch (5). The power supply (9) has an input AC voltage of 220V and an output DC voltage of 12V. Any fan with a supply voltage of 12V and overall dimensions equal to the dimensions of the radiator (3) can be used as the fan (8).

[0018] The device for determining the thermal-oxidative stability of oils operates as follows (Fig. 1).

[0019] The oil samples to be tested are placed on the disk (6) in special steel cups. A thermocouple (7) is installed in the disk (6). The device is connected to the power supply with a plug. The switch (5) supplies voltage to the control unit (4), the solid-state relay (2) mounted on the radiator (3), the inductor (1), and through the power supply (9) to the fan (8). The control unit (4) sets the temperature required to heat the disk and supplies control voltage to the relay (2), which supplies power to the inductor (1). The inductor (1) supplies energy to the disk (6), thereby heating it. The thermocouple (7) monitors the heating temperature of the disk (6), and transmits current data to the control unit (2). The fan (8) and the radiator (3) remove heat from the relay (2). When the set temperature is exceeded, the control unit (2) stops supplying power to the inductor (1).

[0020] Example

[0021] A sample of a purchased batch of fresh TP-22S oil from USK-Uzhovsky was delivered to the petroleum products laboratory of Gazprom Transgaz Nizhny Novgorod LLC. The oil sample must be tested to assess its compliance with thermal-oxidative stability requirements according to STO GAZPROM 2-2.4-134-2007.

[0022] Place oil samples of 4.6±0.2g in four special cups and place them on the disk (6). Install a thermocouple (7) in the disk (6). Connect the device to a 220V power supply with a plug. Switch (5) applies voltage to the inductor (1) through the SSR-50 DA solid-state relay (2) mounted on a plate-type aluminum radiator (3) and controlled by the REX C-100 control unit (4). The radiator (3) and the fan (8), connected to the power supply (9), also powered by the switch (5), remove heat from the relay (2). Use the control unit (4) to set the temperature for heating the disk equal to 180±3°C and apply control voltage to the relay (2), which turns on the supply voltage of the inductor (1). The inductor (1) supplies energy to the disk (6), whereby it is heated to a set temperature of 180±3°C in 9 minutes. The thermocouple (7) monitors the heating temperature of the disk (6), and continuously transmits current data to the control unit (4).The fan (8) removes heat from the relay (2) through the radiator (3). After 4 minutes, the control unit (2) records stabilization of the set temperature with an accuracy of ±1.3°C, which satisfies the requirements of the method for stabilization accuracy (±3°C). When removing the hot cups from the disk (6) after heating at 180±1.3°C for 3 hours, one of the oil samples spilled. The unit was de-energized using switch (5), and the spilled oil was removed from the surface of the disk (6) and the inductor (1) with a rag.

[0023] Thus, the proposed invention makes it possible to increase the safety of determining the thermal-oxidative stability of oils with high accuracy of heating temperature control.

[0024] Using an inductor eliminates the risk of ignition of the test oil vapors, as there is no element with a temperature above the flash point of the flammable liquid. A switch installed at the system input automatically shuts off power to the device in the event of a short circuit or oil spill. Using the control unit as a thermostat eliminates the risk of sparking during operation. The relay is equipped with a heat-dissipating heat sink and a blower fan, ensuring continuous cooling of the thermally loaded relay.

[0025] A radial recess in the top surface, housing a thermocouple, allows for extremely accurate determination of the disk's heating temperature. Connecting the inductor's power input through the control unit and a relay to control its operation ensures precise regulation of the disk's heating temperature.

Claims

A device for determining the thermal-oxidative stability of oils, comprising a heating element, on the upper surface of which a metal disk for mounting samples is located, connected in series with a linear autotransformer and with a thermostat, a thermocouple, characterized in that it additionally contains a radiator, an inductor as a power source and a fan with a power supply unit connected to a switch, through which the entire device is connected to power from a 220 V household network, wherein a solid-state relay mounted on the radiator is used as the autotransformer, the thermostat is a control unit, through which the inductor is connected in series to the switch, and the heating element is a metal disk, in the upper surface of which a radial recess is made for placing a measuring thermocouple connected to the control unit.

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